JPH11290204A - Rice cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the convection of a material to be cooked to a desired form regardless of the configuration of a rice cooker and the configuration of an induction heating coil. SOLUTION: An aluminium layer 2 of a rice cooker 4 is removed or reduced so that an outside stainless steel layer 3 high in temperature upon heating is exposed or comes into close contact with the aluminium layer through a thinner aluminium layer. Thus, a part with temperature higher than that of a peripheral part can be formed in the rice cooker 4 and a lifting convection due to the density difference can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rice cooker utilizing induction heating.

[0002]

2. Description of the Related Art Conventionally, a rice cooker of this kind is, for example, as shown in FIG. In a conventional rice cooker 40, an induction heating coil 42 is provided from below to a side surface of a substantially bottomed cylindrical rice cooker 41 made of aluminum on the inside and stainless steel on the outside.
Are driven by the drive control circuit 43. Reference numeral 44 denotes a temperature sensor which is pressed against and substantially contacts the outer bottom surface of the rice cooker and provides temperature information to the drive control circuit 43.

In the above configuration, the rice cooker 41 into which a predetermined object to be heated such as water and rice has been charged is heated by applying a high-frequency voltage to the induction heating coil 42 according to a predetermined process by the drive control circuit 43. , Cook rice.

[0004]

However, in the conventional rice cooker, the convection of the object to be heated inside the rice cooker is uniquely determined by the shape of the rice cooker and the shape of the induction heating coil. In order to heat the side surface from the bottom surface, it is very difficult to control the convection of the object to be heated into a desired shape while applying sufficient heating power.

[0005] Further, it is difficult to cause an ascending flow in a free place in order to equalize the temperature during low-temperature heating such as cooking prior to water supply of rice while maintaining the temperature at around 60 ° C. It was difficult to control the blow-up. Also, it is desirable that the temperature of the sensor should originally change following the temperature of the object to be heated inside the pot, but it is inevitably strongly affected by the heating of the rice cooker when the cooker is heated.

[0006] Further, the convection in the rice cooker has a convection form in which the convection rises along the pan and descends at the center in order to heat the rice cooker.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention removes or reduces the aluminum portion on the inner surface so that the outer stainless steel portion having a high temperature during heating can be exposed or interposed through a thinner aluminum layer. This makes it possible to form a portion having a higher temperature than the surroundings on the inner surface of the pot, and to obtain a rising convection caused by a density difference.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is characterized in that the outer stainless steel part having a high temperature during heating is removed or reduced by removing or reducing the aluminum part on the inner surface, thereby making the outer stainless steel part close to the exposed stainless steel part through a thinner aluminum layer. On the inner surface of the pot, you can configure a higher temperature part than the surroundings,
This makes it possible to obtain ascending convection caused by the density difference.

According to the second aspect of the present invention, the concave portion is disposed directly above the induction heating coil.
Heat generation of the stainless steel portion becomes remarkable, realizing formation of stronger convection.

According to the third aspect of the present invention, by forming irregularities on the bottom of the hollow, the generation and separation of bubbles near the boiling temperature are promoted, the flow of the object to be heated due to the rise of the bubbles, and the rising of high-temperature steam, etc. This promotes the generation of convection caused by the convection.

According to a fourth aspect of the present invention, rice is cooked by providing the hollow as a substantially circumferential groove in the rice cooker at a position substantially above the temperature sensor and near the inner side of the inner circumference of the induction heating coil. It is intended to suppress disturbance due to heat conduction from the heat-generating portion of the pot, and to further improve the ability to follow the temperature inside the rice cooker.

According to a fifth aspect of the present invention, the induction heating coil is divided into an outer induction heating coil which is provided closer to the central portion and coaxially with the inner induction heating coil through a certain space with the inner induction heating coil. By forming the hollow as a substantially circumferential groove in a portion directly above the space between the inner and outer induction heating coils, heat conduction by the aluminum layer of the rice cooker is suppressed and heating by the inner induction heating coil is performed. And heating by the external induction heating coil can be controlled independently, thereby enabling free convection control.

According to a sixth aspect of the present invention, heat conduction to the side wall of the rice cooker can be suppressed by forming the substantially circumferential groove in a portion corresponding to the outer peripheral portion of the induction heating coil. The flow which rises along the pot which is easy to get up can be suppressed, and the temperature of the side wall of the rice cooker can be freely controlled.

According to the invention of claim 7, claims 1 to
Contrary to the invention according to the sixth aspect, the same effect as the invention described in each of the above-mentioned aspects can be obtained in a state where the inner surface of the rice cooker is flattened by making a part of the heat generating layer into a convex shape so as to be inserted into the heat conductor. Can be obtained.

[0015]

(Embodiment 1) FIG. 1 is a diagram showing a vertical cross section of a jar rice cooker main body 1 (hereinafter referred to as a rice cooker main body) using induction heating as a heat source according to a first embodiment of the present invention.

The rice cooker main body 1 (hereinafter referred to as the main body) is a rice cooker made of a composite metal material formed of a bottomed cylindrical shape having an open upper portion substantially at the center and an inner surface of an aluminum layer 2 and a stainless steel layer 3. 4 is removably built in, and the upper opening 5 of the rice cooker 4 is covered with a lid 6 rotatably fixed at the rear.
A temperature sensor 8 having a built-in temperature resistance element is detachably attached to a substantially central portion of a bottom surface 7 of the rice cooker 4 and has a built-in temperature resistance element therein. And a ring-shaped outer induction heating coil 1 along the bottom surface of the rice cooker 4 and substantially coaxially with the rice cooker 4 with the space interposed between the ring-shaped inner induction heater coil 9 and the space.
0, and a power supply control device 11 for receiving the temperature information of the temperature sensor 8 and controlling the supply of high-frequency current to the inner induction heating coil 9 and the outer induction heating coil 10 in accordance with a predetermined sequence contained therein. Below the lid 6, a rice cooker 4, a temperature sensor 8, an inner induction heating coil 9, an outer induction heating coil 10, and a main body outer shell 12 in which a power supply controller 11 is provided.

FIG. 2 is an enlarged sectional view of a section near the bottom surface 7 of the rice cooker 4. 13A is formed as a hollow provided on the bottom surface 7 of the rice cooker 4 by removing the aluminum layer 2 inside.

In this configuration, the operation will be described.
Is opened, a predetermined amount of rice to be heated and water to be heated, such as water, are charged and energized. When the power is supplied, the power supply controller 11 causes the inner induction heating coil 9 and the outer induction heating coil 9 to follow a predetermined sequence contained therein. 10 is energized. Due to the energization, the stainless steel layer 3 immediately above the inner induction heating coil 9 and the outer induction heating coil 10 on the bottom surface 7 of the rice cooker 4 generates heat. It is transmitted to an object and cooked according to a predetermined process.

In the process of heating and cooking according to the above-described operation, the heated stainless steel layer 3 is exposed inside the rice cooker 4 in the recess 13A, and does not pass through the aluminum layer 2; The temperature of the object to be heated inside the recess 13A rises because the temperature rises rapidly and is higher than the surroundings where the temperature rises via the aluminum layer 2.
By arranging the depression 13A at an arbitrary position in the rice cooking pot 4, a stronger convection of the heated object can be generated, and the temperature uniformity of the heated object inside the rice cooking pot 4 is ensured. This ensures better rice cooking performance.

In this structure, the same effect can be expected even if the recess 13B is formed by thinning the aluminum layer 2 while partially leaving the aluminum layer 2 inside as shown in FIG. .

(Embodiment 2) FIG. 4 is a sectional view showing a second embodiment of the present invention.
3C, the inner induction heating coil 9 and the outer induction heating coil 10
, The temperature of the bottom portion of the depression 13C becomes higher, and a stronger convection of the heated object can be generated, and the temperature uniformity of the heated object inside the rice cooker 4 is ensured. , To ensure better rice cooking performance.

Further, by forming the bottom surface of the recess with irregularities, the boiling at a temperature near the boiling point is promoted, and a more vigorous boiling is enabled. It enables stronger convection, and in addition, promotes the transfer of heat of the hot air flow due to boiling when the amount of water in the latter half of rice cooking decreases, and freely improves the part where heating is insufficient, This ensures better rice cooking performance.

(Embodiment 3) FIG. 5 is a sectional view showing a third embodiment, in which the above-mentioned recess 13E is formed as a groove on a substantially circumference and the inside induction heating coil 9 is formed around a temperature sensor 8.
13E, the heat conduction from the stainless steel layer 3 immediately above the inner induction heating coil 9 of the rice cooker 4 via the aluminum layer 2 is recessed 13E.
Thus, the temperature sensed by the temperature sensor 8 can be made closer to the heated object put into the rice cooker 4. This makes it possible to cook rice more accurately in accordance with the rice cooking process, thereby achieving better rice cooking performance.

(Embodiment 4) FIG. 6 is a sectional view showing a fourth embodiment, in which an outer induction heating coil 9 is provided coaxially with the inner induction heating coil 9 through a certain space. The heat conduction by the aluminum layer 2 of the rice cooker 4 is achieved by forming the hollow 13F as a substantially circumferential groove in a portion directly above the space between the inner and outer induction heating coils 10. While suppressing, the heating by the inner induction heating coil 9 and the heating by the outer induction heating coil 10 are independent,
Heating can be controlled, and free convection control is possible.

(Embodiment 5) FIG. 7 is a sectional view showing a fifth embodiment, in which a recess 13G is formed in the portion corresponding to the outer peripheral portion of the external induction heating coil 10 as the above-mentioned substantially circumferential groove. By doing so, heat conduction to the side wall 4a of the rice cooker 4 can be suppressed.
a can be suppressed and the side wall 4 of the rice cooker 4 can be suppressed.
This enables free temperature control of a. Thereby, better rice cooking performance can be achieved.

It should be noted that any of the above-described depressions can achieve the effects of the present invention regardless of whether the aluminum layer 2 is completely removed or only a part thereof is removed. Similarly, the depressions 13E, 13F, and 13G can achieve the effects of the present invention even if they are not completely closed grooves or not completely circumferential. Although the present embodiment has been described as a rice cooker made of a composite metal material composed of an aluminum layer and a stainless steel layer, the aluminum layer is made of another metal body having good thermal conductivity such as copper, and the stainless steel layer is made of iron or the like. The same effect can be expected for other heating elements based on electromagnetic induction. Further, the effect of the present invention is exhibited even if other metal layers are added.

(Example 6) Contrary to the inventions described in Examples 1 to 5, the inner surface of the rice cooker was flattened by making a part of the heat generating layer convex so as to fit into the heat conductor. In this state, the same effects as those of the invention described in each of the above embodiments can be obtained. At this time, it is a matter of course that irregularities may be provided on the surface of the convex portion, or an annular shape may be provided as appropriate.

[0028]

As described above, according to the first aspect of the present invention, by removing or reducing the aluminum portion on the inner surface, the outer stainless steel portion having a high temperature during heating is exposed or interposed through the thinner aluminum layer. This makes it possible to form a portion having a higher temperature than the surroundings on the inner surface of the pot, and to obtain a rising convection caused by a density difference.

According to the second aspect of the present invention, by arranging the recessed portion directly above the induction heating coil, the heat generation of the stainless steel portion becomes remarkable, thereby realizing stronger convection. I do.

According to the third aspect of the present invention, the formation and unevenness of the bottom of the hollow promote the generation and separation of bubbles near the boiling temperature, and the flow of the object to be heated and the high-temperature steam And the like, which promotes the generation of convection caused by the blow-up.

According to the fourth aspect of the present invention, the hollow is formed as a substantially circumferential groove in the rice cooker at a position immediately above the temperature sensor and near the inner circumference of the induction heating coil. With this arrangement, disturbance due to heat conduction from the heat-generating portion of the rice cooker is suppressed, and the ability to follow the temperature inside the rice cooker is further improved.

According to the fifth aspect of the present invention, the outer induction heating coil is provided coaxially with the inner induction heating coil through a space near the inner induction heating coil closer to the central portion. By forming the hollow as a substantially circumferential groove in a portion directly above the space between the inner and outer induction heating coils, heat conduction by the aluminum layer of the rice cooker is suppressed and the inner induction is formed. The heating by the heating coil and the heating by the external induction heating coil can be controlled independently, thereby enabling free convection control.

According to the sixth aspect of the present invention, the heat transfer to the side wall of the rice cooker can be suppressed by forming the substantially circumferential groove in a portion corresponding to the outer peripheral portion of the induction heating coil. Thus, it is possible to suppress a flow that rises along a pot that is usually apt to occur, thereby enabling free temperature control of the side wall of the rice cooker.

According to the seventh aspect of the present invention, on the contrary to the first to sixth aspects of the present invention, the inside of the rice cooker is formed by forming a part of the heat generating layer into a convex shape so as to be inserted into the heat conductor. In a state where the surface is flat, the same effects as those of the inventions described in the above claims can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a rice cooker according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main portion of the rice cooker near the bottom of the rice cooker.

FIG. 3 is a cross-sectional view of a main part near the bottom of another rice cooker of the rice cooker.

FIG. 4 is a sectional view of a main part near the bottom of a rice cooker of a rice cooker according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a main part near the bottom of a rice cooker of a rice cooker according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a main part near the bottom of a rice cooker of a rice cooker according to a fourth embodiment of the present invention.

FIG. 7 is a sectional view of a main part near the bottom of a rice cooker of a rice cooker according to a fifth embodiment of the present invention.

FIG. 8 is a sectional view of a conventional rice cooker.

[Explanation of symbols]

 1. Rice cooker body 2. Aluminum layer 3. Stainless steel layer 4. Cooking rice pot 5. Upper opening 6. Lid 7. Bottom 8. Temperature sensor 9. Internal induction heating coil 10. Outside induction heating coil 11. Power control device 12. Body shell 13A. Hollow 13B. Hollow 13C. Hollow 13D. Hollow 13E. Hollow 13F. Hollow 13G. Recess 4a. Side wall

Claims (7)

[Claims] 1. A substantially bottomed cylindrical rice cooker in which an inner side is made of a good heat conductor such as aluminum and an outer side is made of a heating element by electromagnetic induction such as stainless steel. A temperature sensor that measures the temperature by contacting with the temperature sensor, and an induction heating coil is provided around the temperature sensor substantially below the rice cooker in a donut shape coaxial with the rice cooker, and a power supply control device that drives the induction heating coil is provided. A rice cooker in which a part of a good heat conductor such as aluminum is removed from the inside of the rice cooker, or a recess is made thinner than the surroundings. 2. The rice cooker according to claim 1, wherein the depression is provided inside the rice cooker directly above the induction heating coil. 3. The rice cooker according to claim 1, wherein the inner bottom of the hollow is formed with irregularities. 4. The rice cooker according to claim 1, wherein the hollow is formed as a substantially circumferential groove, and is provided inside the rice cooker at a position substantially immediately above the inner periphery of the induction heating coil around the temperature sensor and near the inner periphery of the induction heating coil. 5. The induction heating coil is divided into an inner coil which is coaxial with the rice cooker and closer to the sensor and an outer coil which is farther from the sensor, or is separately provided, wherein the recess is formed as a substantially circumferential groove. The rice cooker according to claim 1, wherein the rice cooker is provided inside the rice cooker just above the substantially central portion. 6. The rice cooker according to claim 1, wherein the depression is formed as a substantially circumferential groove, and is provided inside the rice cooker directly above the rice cooker corresponding to the outer peripheral portion of the induction heating coil. 7. A substantially bottomed cylindrical rice cooker in which the inside is a good heat conductor such as aluminum and the outside is a heating element by electromagnetic induction such as stainless steel, and the bottom of the cooker is provided substantially below the center. A temperature sensor that measures the temperature by contacting with the temperature sensor, and an induction heating coil is provided in a donut shape coaxially with the rice cooker substantially below the rice cooker around the temperature sensor, and a power supply control device that drives the induction heating coil is provided. A rice cooker in which the heating element is partially convex so that a part of a good heat conductor is partially inserted therein.